Portland State University master’s students Nicholas Stoll and Travis Glick will present a paper introducing solutions for locating the sources of congestion at the 2016 annual meeting of the Transportation Research Board.

With their faculty advisor, Miguel Figliozzi, Stoll and Glick looked into using bus GPS data to identify congestion hot spots.

By using high-resolution GPS data to visualize trends in bus behavior and movement, the researchers were able to examine the sources of delay on urban arterials.

These visualizations, which can be in the form of heat maps or speed plots like the one shown here on the right (an application of numerical method applied to a 2,000 ft segment of SE Powell), can be used by transportation agencies to identify locations where improvements are needed. For example, adding a queue jump lane at a congested intersection can improve flow.

The researchers used fine-grained bus data provided by TriMet to create the visualizations. Buses have been used as probes to estimate travel...

For the first time, researchers have shown that installing light rail on an existing travel corridor not only gets people out of their cars, but reduces congestion and air pollution.

In the study, planners at the University of Utah measured impacts of a new light rail line in Salt Lake City (University Line) on an existing major thoroughfare (400/500 South). Their analysis showed that traffic near the University has fallen to levels not seen since the 1980s, even as the number of students, faculty and staff at the university has increased, and the commercial district along the corridor has expanded.

"This is the first study to document important effects of light rail transit on traffic volumes,” said Reid Ewing, professor of city and metropolitan planning at the University of Utah and lead author on the study. “Since the University TRAX line opened, there has been increased development in the 400/500 South travel corridor, yet traffic on the street has actually declined. Our calculations show that without the University TRAX line, there would be at least 7,300 more cars per day on 400/500 South, and possibly as many as 21,700 additional cars. The line avoids gridlock, as well as saves an additional 13 tons of toxic air pollutants. This is important knowledge for shaping future transportation policies.”